Circuit tracer



,Sept 1957 H.-s. CHURCH 2,806,203

CIRCUIT TRACER I Filed Jan. 5, 1955 INVENTOR Karo/a 5. C71 arc/2 UnitedStates atent .C RCUITTRACER Harold S. Church, Monterey, Calif.Application January 5, 1955, Serial No. 480,014

" 1 Claim. 01. 324-51 This invention relates to the electrical art, andis specifically directed to a simple but unique device useful in tracingthe presence or lack of presence of electrical energy in wires orelectrical conductors of all kinds.

The primary object of the invention is to produce a circuit tracer whichwill, in a simple and effective manner, visually indicate the presenceor absence of electrical energy in a circuit, and also variantintensities or capacities of such circuits.

A further object of the invention is to produce such a circuit tracer inwhich the visual indicator is preferably an electric light bulb somounted in the assembly that the tracer may be used on circuits ofvariant voltage capacity without danger of burning out the filament ofthe bulb; thus insuring long life of the bulb.

A still further object of the invention is to produce a tracer of thecharacter noted and which, in addition to its function as a circuittracer, may also be used for the purpose of passing a full flow ofelectric energy through a unit where needed in a test of the operativecondition of such unit, or for any other purpose.

A final object of the invention is to produce a tracer made up of fewparts, and one which may be cheaply manufactured and readily assembledor disassembled at will for any purpose.

These several objects are attained by the combination of parts describedin the following specification and defined in the appended claims.

a In the drawings:

Fig. 1 is a side elevation of the complete tracer unit including thecable (foreshortened) for connection with a source of current.

Fig. 2 is a similar view, partly in section, of the unit with the cablebroken oif.

Fig. 3 is a diagrammatic outline of a typical circuit establishedthrough use of the tracer.

Referring now more particularly to the drawings, and to the charactersof reference marked thereon, the numeral 1 designates generally the mainbody of the tracer unit, while the numeral 2 indicates generally thecable leading from the unit 1 to a spring claw clamp or other connectingmember 3.

The body 1 is made up of a solid element of insulating material, andpreferably comprises a frustoconical portion 4 at one end and whichsolid portion is stepped down at the other end by a shoulder 5 to acylindrical portion 6, which latter is cupped out at its free end, as at7.

The numeral 8 designates an electrode which is n1ounted axially throughthe solid element r-6 and projects some distance beyond the end of thefrusto-conical portion 4 and is provided with a sharp point 9 at itsouter end, and with a flanged head 10 at its other end, which head iscountersunk into the cup 7.

A cylindrical sleeve 11 is fitted over the portion 6 and rests at itsinner end against the shoulder 5. The outer end of this sleeve projectssome distance beyond the portion 6 to form a chamber 12.

A cap 13 of non-insulating material is fitted over the extreme outer endof the sleeve 11. A wire 14 is suitably connected with the cap 13 andextends through a flexible insulating tube 15 to a connection with theclamp 3, as at 16.

A compression spring. Wire coil S within the chamber 12 has one end, asat 17, wound tightly around the base 18 of a small incandescent lamp orbulb 19 so that the coil supports the bulb. From the end 17 the coilwire then circles the bulb 19 with widely spaced convolutions, as at 20,and the free end of the coil S is in contact with the cap 13. The springaction of the coil S holds the contact point 21 in engagement with theflange 10 of the electrode 8.

The sleeve 11 and cap 13 are each provided with orifices 22 near theiradjacent ends. Through these orifices any light from bulb 19 may beobserved.

Although not limited thereto, the tracer has been developed preferablyfor use in tracing and testing the various electrical circuits in motorvehicles, and as an illustration of its usefulness in that respect itsmode of operation will now be described.

When the presence or absence of a flow of current through any circuit isto be tested, the user first fastens the clip 3 to a proper point inacircuit to be tested, for instance, to one side of a storage battery B.The user then grasps the insulated body 1 in his hand and touches thepoint of electrode 8 to such other point in the circuit to be tested ashe may select. if current is flowing through the circuit it is thereforeshunted through the tracer, flowing as typically illustrated in Fig. 3.In the showing of this figure it is assummed that the clip 3 is attachedat some point in a circuit leading from the positive side of the batteryB, and that the electrode 8 is contacted at some point in a circuit Cconnected with the battery.

Thus, the tracer will shunt a circuit of electrical energy which willflow from battery B, through clip 3, wire 2, cap 13, resistor spring S,filament of lamp bulb 19, electrode 8, circuit C and to ground. If thecircuit is thus completed the lamp bulb 19 will be illuminated, and thisillumination may be observed through orifices 22. The intensity of thelight will indicate the quality or capacity of the circuit.

The spring S not only serves its function of supporting the light bulb19 and holding its contact point against the electrode 8, but also actsas a resistor so that the tracer may be used on either circuits of sixor twelve volt capacity without overloading the lamp filament; thusassuring the latter of long life. The spring also sustains the lightbulb against severe shock should the tracer be dropped.

The cap 13 being uninsulated, it is possible with the use of the tracerto pass a full flow of energy through a unit where needed in a test. Forinstance, the clip 3 may be fastened on the live side of the coil on thestarting mechanism of a motor, and by touching the cap to the battery afull flow of current may be provided for the starting of the motor.

The tracer is ideal for so-calied trouble shooting in the shop or on theroad. It can be used for locating dead spots in wires by pressing thepoint of the electrode 8 through the insulation of the Wire and intocontact with the wire. It is readily usable to locate bad switches,corroded junctions, burned out units, and various other abnormalconditions existent in various electrical equipment. It may also be usedin setting the timing position on a motor which uses electricity for itsignition, and in this case the ignition switch can be in on or offposition.

From the foregoing description it will be readily seen that there hasbeen produced such a device as will sub- 3 stantially fulfill theobjects of the invention as set forth herein.

While this specification sets forth in detail the present and preferredconstruction of such device, still in practice such deviations therefrommay be resorted to as do not form a departure from the spirit of theinvention, as defined by the appended claims.

Having thus described the invention, the following is claimed as new anduseful, and upon which Letters Patent are desired:

In :an electrical circuit tracer which includes a body having a chamberinitially open at its outer end, an electrode mounted in the body andexposed at its inner end to the inner end of the chamber, and a capremovably mounted over the outer end of the chamber and having anelectric cable connected thereto and in contact with the cap; anelectric light bulb in the chamber between its inner end and the cap andhaving a base in contact with the inner end of the electrode, and ahelical compression spring having a portion of its length surroundingthe base in holding contact therewith, and a relatively large-diameterportion surrounding the bulb in clearance relation and substantiallyfitting the wall 'of the adjacent portion of the chamber; said lastnamed spring portion extending beyond the bulb and at its outer endengaging the cap.

References Cited in the file of this patent UNITED STATES PATENTS1,666,264 Olaneta Apr. 17, 1928 2,459,351 Weincord Jan. 18, 19492,490,830 Norton Dec. 13, 1949 2,534,450 Kadilak Dec. 19, 1950 2,581,116Lewis Jan. 1, 1952

